It is common practice at this time to provide a door, particularly a door which is provided as an "outside" door for a dwelling or other space, with a knobset which may or may not have a lock therein, and a separate lock of the "deadbolt" type. The term "outside" as thus used is intended to mean the primary access to a space and can include the main entrance to an apartment or office within a larger structure. Solid wooden doors and frames therefor are commonly manufactured with no lock openings such that the carpenter or locksmith installing the lock assembly cuts the necessary openings.
For metal door frames it is more difficult to accurately and neatly locate and cut the necessary openings in the frame to receive the bolt or bolts of the lock or locks in the door at the point of installation using conventional hand tools. For this reason, it is desirable to provide such openings at the time of manufacture.
The door and door frame manufacturer usually does not know the specific type of lock which will ultimately be installed in the door and door frame. Deadbolt locks produced by different manufacturers have various physical configurations and can be spaced at various locations along the door edge. For example, the deadbolt lock can be installed independently of a standard knobset with a lock incorporated therein. Alternatively, a combination unit can be installed including the knob assembly with a lock incorporated therein and a separately lockable deadbolt as part of the same assembly. Since these combination units made by different manufacturers are not standardized, the vertical spacing between the knobset center line and the deadbolt center line varies. Thus, the door frame manufacturer does not know the exact size and location of the rectangular opening for the bolt of the deadbolt lock along the length of the door frame. The same problem exists for independently mounted deadbolt lock and knobset devices.
Thus, a need has developed for a system to adapt the opening in a door frame for the deadbolt lock such that the frame can conform to a wide variety of lock styles.